'Southern Star' is a beardless iris with ruffled blooms of vivid red and gold.

Beardless irises aren't really a secret. Gardeners around the world have been growing them for years.

But these perennials areunder-used, says Kevin C. Vaughn, author of Beardless Irises: A Plant For Every Garden Situation. We often plant their more popular, bearded cousins, but beardless irises are beautiful and versatile, he says, and they thrive in a wide range of soils and growing conditions.

Bearded irisies (Iris germanica), as you'd guess from the name, have soft hairs on their falls, or lower petals. These caterpillar look-alikes aren't just pretty accents; they serve a useful purpose by helping attract pollinators.

Beardless irises have what are called colorful "signals" instead of beards, and they serve the same function.

Vaughn's book covers five main groups of beardless irises: Siberian, Louisiana, Japanese, Pacific Coast Native and spuria irises. You'll find a chapter on each, along with one on species and species hybrids. All grow from rhizomes, or modified underground stems.

If your garden space is small, you can find beardless irises that are 3- or 4-inch dwarfs. If you've got plenty of room, look for giants that top out at 6 feet tall. Some irises boast blooms as big as 12-inch dinner plates, Vaughn reports, while others open to just two inches in diameter.

There are also lots of must-have colors to choose from. "Blooms range...from white through black and include the only true red colors in all irises," Vaughn says. "Many of these blossoms have bold signals of contrasting colors, patterns of stripes, dots and stippling and lighter and darker edges. The variety is just incredible!'

Vaughn's book is packed with eye-candy photographs of lovely irises to grow, along with instructions to guide everyone from beginners to experts. If you feel adventurous, dive into the chapter on creating your own beardless hybrids. Vaughn introduced his first iris hybrid at age 18, and today he holds a Ph.D. in plant genetics.

Whether you're an iris enthusiast or a novice, you'll fall for Vaughn's gorgeous images of these easy-to-grow, beardless flowers.

"Beardless irises grow in a variety of climate zones, from Zone 3 to Zone 9 or 10, and in an amazing variety of garden situations." Some prefer wet or dry shade, while others thrive in the sun, whether the soil is acidic or alkaline. There are even beardless irisies for garden spots with shallow, standing water, or spots that flood from time to time. "These are often sites that are difficult for the gardener but the beardless irises not only tolerate but burgeon in these garden locations. "

Try combining beardless irises with other perennials in mixed borders; many work very well. "When the irises are not blooming, the upright foliage has the effect of an ornamental grass, but one with gorgeous flowers, too. "

You can practically stow that shovel, says Vaughn, since these kinds of irises can remain undisturbed for a long time. "Unlike the more familiar bearded irises, most beardless irises don’t require constant digging or dividing. Rather, plants may be left in place for years, with the clumps improving in size. Few perennials offer this sort of performance."

Don't be afraid to let beardless irises mingle with your native plants. "Many beardless iris species that have been less well known in the past are finding increasing use in the garden and being used in wild or native plantings. Both the Pacific Coast Native and Louisiana irises are American wildflowers and can fit well into wildflower gardens. "

Look for recent improvements in beardless iris hybrids, Vaughn adds; you'll find much to love in their colors and shapes, and in the patterns of the flowers. "Many of the cultivars of Siberian irises are showing tendencies towards repeat bloom. The gardener today has an abundance of wonderful choices that will enhance their gardening experience."